Linear alkylbenzenes (LAB) are compounds that have significant commercial importance. Linear alkylbenzene sulfonate (LAS) compounds made by sulfonation of linear alkylbenzene are used in the manufacture of detergents and other products. Because linear alkylbenzenes are more easily biodegradable than branched alkylbenzenes, linear alkylbenzenes have essentially replaced branched alkylbenzenes in detergents and other products. In particular, linear alkylbenzenes with long alkyl chains, such as chains having about 10 to about 14 carbons, are commonly used. However, linear alkylbenzenes with longer chains and with shorter chains also are commercially important.
Linear alkylbenzenes often are made by alkylation of benzene with olefins. Positional isomers, such as 2-phenyl, 3-phenyl, 4-phenyl, 5-phenyl, and the like, result from this alkylation of benzene with long chain olefins. The distribution of the phenyl along the alkyl chain produces different products.
Historically, linear alkylbenzenes have been manufactured commercially using Friedel-Crafts condensation employing catalysts such as aluminum chloride, or by using strong acid catalysts such as hydrogen fluoride, for example, to alkylate benzene with olefins. In 1995, a solid bed alkylation process, the Detal™ process, using a solid non-corrosive acid catalyst was introduced.
Current LAB manufacturing processes employing solid alkylation catalysts use kerosene-based C9 to C16 material from a Pacol™ dehydrogenation process, which is typically a mixture of about 9-15% olefins in paraffin.
Gas-to-liquid (GTL) technologies for the generation of C9 to C16 range of hydrocarbons have raised interest in the possibility of producing LAB using a GTL-based feed source. The ability to use a GTL feedstock would reduce dependence on crude-based feedstocks.
Dialkylbenzenes made from C10 to C13 olefins and benzene have been recognized as promising candidates in tertiary oil recovery applications and for use as lubricants. Demand for dialkylbenzenes has been steadily increasing in recent years.
Currently, there is no commercial process to make dialkylbenzenes as a primary product. They are presently produced in small quantities as a side reaction in the manufacture of linear alkylbenzenes. The typical ratio of dialkylbenzenes:linear alkyl benzenes in a linear alkylbenzene complex is about 1-5 wt %, which is too low to support the increasing demand for dialkylbenzenes in the face of relatively steady demand for linear alkylbenzenes.
Thus, there exists a need for methods for making dialkylbenzenes.